ashvarybabul said:Canon 55-250 IS is certainly the best option inside your budget..
However, If you succeed in extending the budget bit more, you can look forward to Tamron 70-300mm VC
Not sure of the exact price but it is 20+ k
I recently used this Tamron 70 - 300 mm VC on my Nikon D90 and its VC (IS in terms of Canon and VR as in terms of Nikon) was awesome, once it loocked on target it never moved a little.
Very very recommendable if the budget is permitting.